This “precautionary” step includes more than 20 embassies in the Middle East, North Africa, and South Asia. According to an unnamed Bloomberg source in the State Department, this includes embassies in “predominantly Muslim countries, and also in Israel, where the workweeks include Sundays.”

The State Department told NBC yesterday that the threats to the embassies, and now deductively to travelers, were “al-Qaeda related.”

MORE: Closure of US Embassies on Sunday stems from an al Qaeda-related threat originating from the Middle East, US officials tell NBC News